added a 'default-reify' function that works for neq, symbolo, numbero, and absento.  also cleanup
absento cleanup
pulling in all the tests from the current version of miniKanren, reformatting the tests directory
added a testing module to testall.rkt, run `raco test testall.rkt` to run the longer tests in the test files, simply run `racket testall.rkt` to run the short tests